So my gun ('09 pilot) has a slow leak from the valve. The problem seems to be the cupseal, I swapped it out for the 2nd one I have but that one leaks too. I tried unscrewing the valve pin a bit from the cupseal and it stopped the leak for a while but it came back. I think the hammer hitting it screwed it back in but that's a stretch. Its very strange it comes and goes randomly, the only other thing I think it might be is the valve spring. Can they become over-compressed after a while and not push hard enough on the valve?

ALSO i removed and carefully inspected the valve body but it seemed perfect and had no dings or scratches in it.

Are you sure its the cupseal and not the valve o-ring thats leaking? You might try putting some oil in there and see if it does anything.

I'm sure, because the valve o-rings were perfect and I re-oiled them before I but the valve back in, also when I messed with the cupseal the leak stopped for a bit and came back. This happened once before and I just swapped the cupseal and it stopped but now its back

Make sure you cock the marker before airing it up.
It seems unlikely that its valve spring is worn out, but I guess its possible. By any chance did you look at the face of the valve while you had it out?

Make sure you cock the marker before airing it up.
It seems unlikely that its valve spring is worn out, but I guess its possible. By any chance did you look at the face of the valve while you had it out?

yes I looked at the rim that the cupseal contacts with it is 100% perfect no scratches nicks or anything wrong with it. Its odd because I unscrewed the valve pin from the cupseal about 1cm and the leak stopped but as soon as I shot it it came back. Its a very slow leak, and can only be heard if you put your ear to the feedneck. Also I am cocking it when I air it up. I'm low on air but it does this no matter how much is left in the tank.

Wow strange! Is your velocity where it should be? I guess trying a replacement spring is a cheap fix if you have a spring kit handy. You can cut down a spare mainspring if you had one of those instead.

Wow strange! Is your velocity where it should be? I guess trying a replacement spring is a cheap fix if you have a spring kit handy. You can cut down a spare mainspring if you had one of those instead.

Im going to have to try that, I don't have any extra springs so I might try a spring kit. The velcity adjuster is all the way out does that make a difference?